Field of the Invention
The present invention relates to an intermediate transfer member, and an electrophotographic image forming apparatus using the same. More specifically, the present invention relates to an intermediate transfer member which generates less cracks and scrapes even if used repeatedly for paper having irregularities, and can transfer the secondary transfer image excellently, and an electrophotographic image forming apparatus using the intermediate transfer member.
Description of the Related Art
As an image forming method of forming an image at a high speed and obtaining a high quality toner image, there is a method of forming an image through a process of developing an electrostatic latent image on an electrostatic latent image carrier with toner supplied by a developing roller, and transferring the formed toner image onto a transfer material such as a paper sheet or the like via a member such as an intermediate transfer member.
For the intermediate transfer member to be used in this image forming method, favorable toner transferability from an electrostatic latent image carrier to an intermediate transfer member, and also from the intermediate transfer member to a transfer material, and further a cleaning performance to finely remove the residual toner after the transferring, are required.
In the electrophotographic image forming apparatus in recent years, various transfer materials are used, and is required to correspond not only to plain paper or OA special paper but also to thick paper, coated paper, and further to some kind of paper such as paper having irregularities on the surface (hereinafter, also referred to as “paper with irregularities”). In particular, the paper with irregularities to which emboss processing has been applied is increasingly used for a business card, a cover of printed matter, and the like because of the peculiar texture.
In order to form a favorable secondary transfer image onto thick paper, or paper with irregularities, use of an intermediate transfer belt capable of absorbing the thickness and irregularities of an object to be transferred (recording paper) as an intermediate transfer member used in an electrophotographic image forming apparatus, can be considered. For example, by giving elasticity to the intermediate transfer belt, a surface of the intermediate transfer belt follows thick paper and paper with irregularities, and improvement of the transferability can be expected.
However, the elastic body has a soft surface and a high frictional property, therefore, when print of a large number of sheets is performed by using paper with irregularities, the surface is scraped, and the expected effect cannot be obtained. As to the countermeasure, it is known that the hardness of an elastic layer on a surface of an intermediate transfer belt is increased, and a coat layer is arranged on a surface of an elastic layer (see, for example, JP 2011-22271 A). However, when the hardness of an elastic layer is increased, the transferability of paper with irregularities is decreased. Further, the coat layer cracks in the bent portion in a copying machine when being extremely hard, and the part cracked in a low density image such as a half-tone image falls out in streak lines. Conversely, when being soft, there is a problem that the surface is scraped by a photoreceptor sliding with an intermediate transfer belt or by a cleaning system, and the transferability is decreased.